The present invention relates to a vertical blind mechanism in which the vanes are mounted for traversing movement on a header across a window opening between an open and a closed position, and also for angular rotation about an upright axis for light control. Some prior vertical blind mechanisms, for example, as disclosed in U.S. Pat. Nos. 2,755,854; 4,006,769 and 4,257,470, mount the vertical vanes on rotary vane supports for traversing movement along the horizontal header and directly connect the vane supports to a pair of flexible cords or bead chains at fixed locations therealong so that the cords or bead chains control the spacing between adjacent vane supports when the vanes are drawn along the header to a closed position, and the cords or bead chains are also manipulatable to control rotation of the vane supports. In these prior vertical blind mechanisms, the cords or bead chain were connected to the vane supports at locations outside the header and the exposed cords or chains not only adversely affected the appearance of the blind mechanism when it was drawn to a closed position, but also drooped or sagged between the vanes when the blind mechanism was drawn to an open position. Further, direct connecting of the cord or bead chain to the vanes also limited the maximum possible angular rotation of the vanes so that it was difficult to rotate the vanes through a full 180.degree. as is desirable for complete light control by the vanes.
Prior vertical blind mechanisms have utilized a header having a slot along the bottom of the header with the vane supports mounted in the slot for movement along the header. However, when the slot is at the bottom of the header, the slot and some of the blind operating mechanism as well as the undecorated interior of the header is exposed to view from the room side of the blind mechanism. In addition, the operating cords for the traverse mechanism sometime droop into and through the downwardly opening slot in the header.